Field of the Invention
Engineered crosslinked thermoplastic particles are useful for interlaminar toughening of composite materials.
Description of the Related Art
Various types of particles have been used to alter the properties of composite materials. In particular, un-crosslinked thermoplastic particles have been used in thermosetting resins but have been associated with various problems. One problem occurs as the concentration of thermoplastic increases. High concentrations of compatible or soluble thermoplastic particles in a resin, which might lead to their dissolution in the resin, causes the combination to be susceptible to phase inversion resulting in poor environmental resistance. Other problems occur with thermoplastic particles that dissolve during curing because the resulting composite does not retain sufficient of its thermosetting thermomechanical properties. Other insoluble particles do not allow the resin material to penetrate the particles causing a debonding between the particle and the resin, which does not confer sufficient strength to the composite material.
Engineered crosslinked thermoplastic particles, which are used in resin systems described herein, overcome these and other disadvantages of conventional particles.